Wow awesome thread. Here's some of the cabs I just can't live without:
1) A working weather city editor for winmo 6.5 Sense UI (I'm currently on MightRom with sense)
2) An awesome QR code reader.
3) A resistor color code help program. You just enter the color bands and it outputs the resistance value in ohms.
4) This is a great network analysis application. Has almost all the major network utilities that can be found on your PC or linux box. Stuff like and IP subnet calculator, a strong password generator, Whois, Timer Service (connects to time servers and retrieves the time), DNS lookup, HTML downloader (will download html source from url you give), Finger, Wake o LAN client, DNS auditor (will perform a dns query on specified range of IP's), Port Scanner, traceroute, Ping Sweeper (ping a range of IP's) and standard ping, And a network info function that shows all the network information on your current phone (Ip address/subnet/gateway/dns/etc for your adapters). Very handy. Works best when your connected to a network via wifi. The icon for it has messed up colors, but its always been that way on every device I install it on. Works great tho.
Also would like to recommend the program
1-Calc by Omega One Software. It does cost $30 for the program (I paid $45.99 total for the program and a skin pack) but for me it was waaaay worth it. You don't have to buy the skin pack to customize the look though, I'm just really lazy and didn't want to put the effort into it. It does so many things and I desperately needed a good scientific calculator for my Electronics courses. Just look over the features list and you will realize how powerful it really is. The stock skins make the calc look dated, but don't let that fool you. This thing is better than some of the TI calcs I've had. Very well worth the money for me. When you buy the expansion (which includes skins) you get a Windows XP/Vista/7 version of the calc.